Generally, in a room temperature environment (such as 10° C. to 40° C.), heat generated by electronic devices is required to be removed. For example, in an electronic device with a fanless system, heat sources are directly in contact with a casing of the electronic device, such that heat generated by the heat sources is transferred to the surface of the casing, and then is dissipated to outside air via radiation and convection.
On the other hand, in a low temperature environment (such as −40° C.), electronic devices are required to be heated up before being turned on. If an electronic device is turned on at a low temperature, the electronic device may be damaged, and therefore its service life is shortened. Hence, when an electronic device is operated in a low temperature environment, the electronic components inside the electronic device should be heated up to a safe temperature (such as 0° C.) before the electronic device is turned on in order to protect the electronic components and extend the service life of the electronic device.